1. Field of the Invention
The present invention relates to an automatic transmission equipped with a planetary gear unit, and, in particular, to a mechanism linking a ring gear and its support member.
2. Description of the Prior Art
Recently, the applicant of the present invention proposed an automatic transmission, as disclosed in Japanese Laid Open Patent No. SHO-62-141341, wherein this automatic transmission is provided with a planetary gear comprising a single planetary gear and a dual planetary gear. Sun gears of these two planetary gears are integrally connected together, and carriers of these two planetary gears are also integrally connected together. The carrier is linked to a counter-drive gear which serves as an output member, an input shaft and a ring gear of the single planetary gear are linked through a first clutch, the input shaft and the sun gear are linked through a second clutch, the sun gear engages a second brake through a first brake of a first one-way clutch, and a ring gear of the dual planetary gear engages a third brake or a second one way clutch, whereby an automatic transmission mechanism section with a forward three speed is provided by operating these clutches and brakes.
An outer race of the second one-way clutch is integrally secured to and supported by a forward end of the ring gear of the dual planetary gear, specifically, a ring gear of larger diameter. A support plate extending to the inner radial side is secured to a rear end of this ring gear. The support plate is free rotationally supported between a tip side carrier which supports a pinion of the dual planetary gear and the ring gear of the single planetary gear through a thrust bearing. Accordingly, a space is maintained between the side surface of the second one-way clutch and the carrier side surface.
In addition, the applicant of the present invention has proposed, as disclosed in Japanese Laid Open patent No. SHO 63-145846. an automatic transmission wherein the ring gear of the above mentioned dual planetary gear is supported by means of a disk-shaped support member and the automatic transmission itself is anchored to a support member by means of a snap ring.
Accordingly, in Japanese Laid Open Patent No. SHO-62-141341, the lubricating oil supplied to lubricate the second one-way clutch flows out through the space between the carrier and the side surface of the second one-way clutch and the space between the ring gear of the dual planetary gear and the carrier, so that the second one-way clutch is not properly lubricated, and during high speed rotation in particular, this can cause seizure of the one-way clutch.
Also, as disclosed in Japanese Laid Open Patent No. SHO-63-145846, the ring gear R2 of the dual planetary gear is supported by a disk-shaped support member 4 and anchored by a snap ring 3'. As indicated in FIG. 2b, because the snap ring 3' is simply engaged in the indented channel 14' to prevent the snap ring 3' from ejecting, a space k is created between the outer race 17 of the one-way clutch and the support member 4, and the lubricating oil flows out from the space k, so that the one-way clutch is not properly lubricated. In the same way as previously outlined, during high speed rotation in particular, this can cause seizure of the one-way clutch.